Global warming underestimated?

Are the official estimates of a 1.4° to 5.8°C (2.5° to 10.4°F) increase in global mean surface temperatures by the year 2100 significantly in error? That was the conclusion of MIT professor Dr. Peter H. Stone, in a lecture I attended last week at the annual meeting of the American Meteorological Society. Dr. Stone's results were also published January 13, 2006 in Geophysical Research Letters. The "official word" in the science of climate change comes from the United Nations-sponsored Intergovernmental Panel on Climate Change (IPCC), a collaborative effort between over 2,000 scientists from over 100 countries, including many of the top climate researchers in the U.S. The IPCC publishes an extensive assessment of the state of the science every six years. The most recent report, issued in 2001, predicted the 1.4° to 5.8°C increase. If Dr. Stone is right, the next IPCC assessment, due out in 2007, will have to revise that estimate upwards.

Dr. Stone started his talk by posting this quote from the Executive Summary of the 2001 IPCC model evaluation chapter: "Confidence in the ability of models to project future climates is increased by the ability of several models to reproduce the warming trend in 20th century surface air temperature when driven by radiative forcing due to increasing greenhouse gases and sulphate aerosols." (The term "forcing" in climate research refers to any process, natural or human-caused, that "forces" the climate to respond in a significant way.) The IPCC report supported their statement by comparing climate simulations of the observed 20th century climate that used just natural processes ("forcings" such as volcanic eruptions and natural changes in the sun's brightness) with simulations done including human-caused "forcings" (greenhouse-effect gases added since pre-industrial times, plus aerosol particle pollution). Dr. Stone presented Figure 4 (below), a modified version of a figure from the 2001 IPCC report. The figure shows a typical 20th century climate simulation by one of the major climate models used for the IPCC assessment--the UK Hadley Center model. The results look good. The model is able to reproduce the observed climate of the 20th century. In addition, the simulation shows that one cannot explain the observed 20th century global warming of 0.6°C without including human-caused (anthropogenic) climate forcings.

Dr. Stone argued that the IPCC's confidence in the ability of models such as the UK Hadley Center Model to predict future climate was invalid, and that the good agreement between the observed climate and model prediction seen in the figure above could have been coincidence. He outlined several ways that compensating errors in two or more areas of model uncertainty could have produced a climate simulation that matched the observed 20th century record.

Major uncertainties in climate change computer models include:

1) Climate Sensitivity (how much global surface temperature changes when CO2 is doubled)2) Rate at which the oceans take up heat3) Strength of forcing by aerosol particles4) Natural variability

For example, if a model has a Climate Sensitivity that is too great (the model predicts too much warming for a given increase in CO2), and improperly assumes too much cooling will occur due to pollution from aerosol particles, the two errors will cancel each other out and lead to a realistic-looking simulation. The Climate Sensitivities of the 11 key models used to generate the 2001 IPCC results varied by about a factor of 2.5, from 1.5°C to 4.5°C. Similarly, the amount of heat taken up by oceans varied by about a factor of 2.5 in the models. Additional uncertainties exist in the models' treatment of aerosols and natural variability.

Rather than dismiss the climate models as being too filled with uncertainty to be useful for performing climate simulations, Dr. Stone maintained that one can do an intelligent uncertainty analysis by varying two of the major uncertainties in a model simultaneously, and study the resulting model predictions. He described his group's research to evaluate the uncertainties in 11 of the key models used to formulate the 2001 IPCC climate report. The study was done using data from the Coupled Model Intercomparison Project (CMIP), an international research program begun in 1995. The talk then became quite technical, with several plots showing Probability Distribution Functions on parameter-space diagrams. It was at this point I bemusedly watched the audience member next to me who hadn't had enough cappuccino that morning repeat the classic pecking bird "doze-droop-jerk-I'm awake!" pattern. Meteorology talks aren't always filled with captivating displays of 3-D Category 5 hurricanes! There's a lot of hard science needed to understand the concepts.

Finally, Dr. Stone finished his uncertainty analysis, and he presented some rather startling conclusions:

1) Models have been over-estimating the rate of mixing of heat into the deep ocean.

2) This implies that their projections of surface warming for the 21st century are too low.

The guy next to me jerked fully awake now, and the audience got noticeably more attentive. "And this worries me," Dr, Stone continued. "It worries me enough that we've made many extensive tests of our methodology that try to make sure that there are no flaws. I would be delighted if anybody here could come up with a test that we might look at to see if we've done anything wrong." The audience, filled with several hundred people, including many of the world's foremost climate experts, was silent. No one could come up with a reason to dispute Dr. Stone's gloomy conclusion.

So how much in error are the climate models? Dr. Stone didn't give a number in his talk, and when I asked him about this later he said he had only a rough preliminary idea of what this error might be. His research team is currently analyzing their results to see how much additional warming we can expect. When they publish some specific error estimates, I'll be sure to post a follow-up blog on the subject.

Professor Stone's talk can be heard on-line for free. To do so, you must install the free WebEx player for IE or Netscape. Note: this will not work for other browsers, such as Firefox! The talk is about 40 minutes long, and includes figures. Alternatively, you can read the paper on the subject that he co-authored along with C.E. Forest and A.P. Sokolov of MIT's Joint Program on the Science and Policy of Global Change:

A free abstract of the paper is available from the agu.org website. A full version costs $9 for non-subscribers.

A note on my global warming blogsIn an issue as complex, contentious, and important as global warming, it is impossible for anyone to present an unbiased and fair treatment of the subject. My bias will be towards presenting new scientific findings published in peer-reviewed journals, as well as calling attention to the political aspects of the debate when it appears that one side or the other is attempting to twist or hide the truth. While thus far I have only focused on the NASA/Dr. James Hansen affair, I also have criticism of those claim that Hurricane Katrina was significantly enhanced by global warming. Although it is possible that global warming did contribute significantly to Katrina's intensity, the current best hurricane science supports only a 1-2 mph enhancement in Katrina's winds by global warming. I have a blog on this topic I plan to post next week, highlighting recent questionable statements by the editor of Science magazine on the matter.

For those of you following the NASA/Dr. James Hansen affair, see this morning's New York Times article, where George C. Deutsch, the young NASA press aide who resigned on Tuesday amid claims that he had tried to keep Dr. James Hansen from speaking publicly about global warming, defends himself publicly.

A note on media bias on the global warming issueI'm of the opinion that articles in the New York Times on global warming tend to be biased in favor of dramatizing the problem and calling for action. Articles in the Wall Street Journal, Washington Times, and Newsweek magazine generally have the opposite bias. Time magazine seems pretty neutral, and CNN.com may have a pro-action bias. I'm not sure about the USA Today, Washington Post, or other sources. One of my favorite sources of global warming info (but a little too technical for many readers) is from realclimate.org, which is maintained by some of the top climate scientists in the field. They have serious disagreements with the Wall Street Journal.

The problem is in the semantics...when the left talks about "global warming", what they REALLY mean is "evil greedy fascist corporation big oil funded human caused global warming" not just the simple term "global warming".

Global warming, while it may indeed be happening at this time, is almost certainly the result of natural climate cycles, not the industrial revolution...although it is impossible to know for sure either way, because we don't have a spare Earth to use as a control group.

I don't think the ice caps have really shrunken that much. They are smaller, but remember that the oceans contain a *trenedous* amount of water - even if the ice caps were to totally melt, ocean salinity would only drop by a few %.

Wow! I'd like to be in NYC right now! 12" already on the ground in Central Park, zero visibility at La Guardia and a band of 2-4" per hour snowfall moving in. This looks to be a Top 5 storm for the area. I think New York will get the max amount, although it's going to be pretty impressive for southern New England, too.

I'm not a scientist and don't even play one on TV, but some of Gray's arguments pooh-poohing the relationship between global warming and hurricane intensity seem willfully tunnel-visioned. In his 2006 forecast, for example (http://hurricane.atmos.colostate.edu/Forecasts/2005/dec2005/), he says this:

"[The] large increase in Atlantic major hurricanes is primarily a result of the multi-decadal increase in strength of the Atlantic Ocean thermohaline circulation (THC) which is not directly related to global temperature increase. Changes in ocean salinity are believed to be the driving mechanism."

I was under the impression that the size of the polar ice cap, which is shrinking pretty dramatically, has a direct bearing on ocean salinity. So this argument makes no sense to me. Maybe some of you who are scientists can help me out on this one.

It is interesting, as the WSJ article noted, how most of the long time tropical climatologists are in the natural-cycles camp and most of the statisticians are in global-warming camp. I suspect they're both right: We have a natural cycle being magnified by global warming.

Regarding global warming, although a very divisive issue, there is alot of conflicting data that leaves too much to personal interpretation for there are so many variables involved some as seemingly insignificant at first glance as hea inducing asphalt of all things.

I will on record and say that although I believe the DIRECT(key word here for me)of these global temperature increases are a result of Natural causes, that I will not say that greenhouse gas emissions have had no effect whatsoever.

Once again, this is simply my personal perspective and I respect the views of those with a dissenting opinion for either of us COULD be correct in all reality.:)

When I interned at the NWS, we didn't make any adjustments for such temperature readings. This is based solely on my own personal experience and maybe others with meteorological experience such as Dr. Masters obviously or Weatherguy03 (Bob) might have a different experience and know if this standard still exists. In other words, I don't think there is any adjustment made for relocation of NWS observation sites.

It is nice to meet you Mark and an excellent post I may add. Likewise, St. Simons response was equally as impression.:)

I choose to personaly keep all discussions of religion(which is ones personal belief and should be respected), political preferences (another personal choice of beliefs), and thje like out of future discussions. These type of discussions seems to quickly become personal yet I don't view them as being anymore PERSONAL than a respectful disagreement over the DIRECT cause of global temperature increases.

Once again, these are simply my personal opinions and I hope each of you will respect my views as I do yours and will not make any differences of opinion personal as I unfairly did myself earlier in this blog with Dr. masters unjustly for which I sincerely and rightfully apologized. I hope you all have a great weekend.:)

StSimons, a very good point about our data and why any data gathered in and around large metro areas has to be taken with a grain of salt. In Denver our official site was downtown from 1872 through 1949, then at the old Stapleton Airport about 7 miles ENE of downtown from 1950 through February 1995, and at Denver International Airport about 20 miles NE of downtown since March 1,1995. The current site at DIA is in mostly rural surroundings. However, another complicating factor is the switch to automated instruments in the past 10 years or so. ASOS has to be recalibrated frequently and has been known to record maximum temperatures several degrees F higher than other nearby locations. I recall reading an article about problems with the data reported from Newark,NJ about 10 years ago, where the instruments were exposed near a large parking lot. That much said, the increase in summer highs in Denver did begin in the late '80s at the old Stapleton site before the automated system was commissioned. I'm trying to compare data from reliable sites away from large cities to get a better idea of how much warming we've had. With all these data sets that are quoted, one does have to wonder what adjustments are made for urban heat islands which have developed over the years. It is significant that a steady warming trend is noted from the 1880s through the 1930s, then a slight cooling from about 1940 through the 1970s, then a strong warming since 1980. Many weather stations were located in downtown areas during the first period, then moved out to airports around World War II. The airport stations were often in rural surroundings for many years, then began to be surrounded by urban development in the last few decades. The moves in station locations might account for some of the trends if proper adjustments have not been made for this. But this wouldn't account for all of the warming observed since 1980. I'm not an expert on this, would someone know exactly how adjustments are made to the data to account for changes in location and exposure of instruments,changes in observation times,etc.?

I hope you saw my reply and understand that I personally don't consider anyone who engages in homosexual activity to be the same as the skin tone we are born with.

That was a very unfair assumption and comment on your part to label me as a bigot of all things in my personal opinion. I honestly believe that no one is better than another for any reason regardless of skin tome, intellect,gender,health, education,or anything else for that matter. Please keep in mind I was responding to Stormchasers questions about the Biblical view of homosexuality and Inyo's remarks as well. I was giving my opinion based solely on my interpretation of the Bible where it says it is a blatant sin equivalent to lying, murder, adultery, idolatry, etc.

My personal opinion based strictly upon that is that people are not born homosexual just as no one is born a murderer or adulterer, but we choose to sin(all of us whether bigger or smaller sins) Anyone who thinks a certain race or gender for example is more superior than another is engaging in bigotry which I did not nor ever would!

Half of my personal FRIENDS are of a different race but we all were created by the same CREATOR in my personal opinion who chose what we might look like which we had no part in. We are all created EQUAL and no one should think they are better than another. Our actions define who we are and that is what God will ultimately hold us accountable for in my opinion.

Naturally, I have a right to dislike the SIN of homosexuality as I do the sin of murder according to my own personal Biblical view and that is not bigotry no matter how you or anyone tries to suggest otherwise. To be a bigot, I have to dislike or even hate the PERSON engaging in such activity which I do not for I too am not without sin.

Most importantly based upon your very unfair suggestion and comparison with racial overtones, I personally don't consider race, gender,nationality, or anything else that God chose for us to make us better than another nor should anyone else. I HATE all forms of bigotry that exists including those of whites thinking they are superior than blacks and vice versa. Likewise, I HATE the personal SINS that I find myself succombing to but I would hope someone wouldn't HATE me because I sin when everyone does the same. That being said, it doesn't mean anyone should accept my sins of adultery if I were to do so for it is my CHOICE if I choose to engage in such activities and not something that was chosen for me like skin tone as in your inappropriate comparison. I would sincerely hope you also agree than none of us are better than another for any of the aforementioned reasons as well. For who are we to judge another. But, we have every right to dislike a specific sin like murder, homosexuality, and lying to name a few.

I hope you better understand my views and realize that even if you disagree with them that I am in no way being a bigot(for I have to have hatred of a person and not their actions to be so).

Otherwise, I enjoy all of your respectful and knowledgeable comments. I wonder if my critique of STORMTOPS inaccurate forecasts as I personally viewed them hasn't given the impression that I somehow think I am personally better than another for that was NOT the intention of that blog. That blog was written at the encouragement of Califonia to clarify WHY I didn't agree with my good friend, Califonia's interpretation of STORMTOPS forecasts outperforming the NHC which I viewed as both inaccurate and completely unfair. It was by no means to be personal because I gave him all the credit he earned when he did outperform the NHC early in the forecast period and noted his forecasts were his sincere beliefs. We will all make errors in forecasting but I don't think it is fair to see the NHC be consistently bashed as not performing as well on Katrina as STORMTOP when the Truth clearly shows otherwise as evident by my blog comparing each forecast in their own words(not mine).

Anyways, I will most disappointed if you read all of this and still somehow believe I could ever be such a horrible thing as a bigot. Regardless, thanks so much for reading this email and I hope you have a great weekend.:)

I realize that some wil view this as an inappropriate and unnecessary post. However, I have chosen to post it nonetheless to clarify any misunderstanding or incorrect perception of those who read or will read the posts contained in this blog precedding this post. Please realize I wasn't the one who chose to bring up these topics but when asked, shared my personal opinions on such matters. I could very well have simply posted this in my blog but then again, it is likely many wouldn't have seen it there since the discussion was brought up in this blog.

I have no concerns that one may take issue with my personal views for we all can respectfully disagree without demeaning the person. I find it completely unfair to label a person as a "bigot" of all things when that is absolutely unjustified as hopefully explained in the comments that follow. I will post these comments in the next post to shorten the long monologue as many will call it (lol).:)

Hi! I've been lurking since last fall and have enjoyed the blog very much, so I decided to join and support WU. I'm from the Denver, Colorado area. The land of springy winters and wintry springs! We usually have very little snow in mid winter and lots of snow in March and April. After weeks of no winter, we finally had 2" of snow yesterday morning and down to 5 above this morning. The northern mountains of Colorado have had a great snow season, southern Colorado hasn't fared so well. Rather typical of La Nina in our area. Just to introduce myself, I grew up in the Chicago area (that's why I enjoy winter) and have been a weather geek since I was a kid back in the '60s. I work outdoors in city park maintenance so weather is a key factor in my job every day. One thing is for sure - we do a lot less snow removal than we did 20 years ago. On global warming, I was a skeptic back then, but have no doubt the climate has warmed dramatically since the '80s. Besides the lack of snow in Denver in recent years, our summers have become much hotter. Almost half of the 100 degree days ever recorded in Denver since 1872 have occurred since 1989! Last summer we had 7 days reach 100 or higher, including tying our all-time record of 105. I like to compile historical data, and comparing the numbers for stations away from large metro areas, the warming trend since the '60s and '70s is dramatic. As to the cause of global warming, I take a position in the middle. I don't see how we can add CO2 and other gases to the atmosphere and not alter the climate. However, I don't think the warming is 100% due to human activity. One observation I would make is that while the US has been very wasteful of our resources over the years, our emissions of greenhouse gases are not increasing that much now. The climate has really heated up in the past 10 years, which coincides with a dramatic increase in fossil fuel consumption in China, India and other "developing" nations. I feel the US needs to take it's own steps to reduce oil use (higher fuel economy standards for vehicles would help and nuclear power does need to be looked at again). However, I am not in favor of the US signing on to Kyoto or a similar treaty unless it includes China, India, Brazil, Mexico, etc. Smaller, very poor nations could be exempted. One interesting twist to consider, though, is that oil production will peak soon and oil prices will soar. This will do much to bring about conservation and development of alternate energy sources. Large SUV's will rapidly disappear when gasoline is $10 per gallon. But I prefer to let the marketplace do its job, rather than impose excessive taxes that would damage our economy and be squandered by corrupt politicians on their pet programs or on more wars around the world. Well, that's my soapbox. I would like everyone to know that I will treat you with respect whether we agree or disagree on issues. I am not going to get into heated arguments or make fun of anyone. I am a Christian man, and that is my world view. However, I think is important to stay on topic here in the blog. I will post my beliefs, etc. in my own blog which people can visit. Anyway, I'm glad to join you and have a great day! MarkLink

My 2 cents again......Guys this IS Dr. Masters blog.....If it offends you, then dont read it. We do have that choice.Chaser, I am real proud of you apologizing like you did. I ALWAYS look forward to debates with you. Man, we are obviously 2 totally different people but, I respect your views always!! I hope things are going better for you now you are out of the hotel.BTW, Has anyone seen anymore on the weather ball??Really want to see that thing in motion!!!!

i wasn't picking on cyclonebuster, please read what i said and make common sense of it please. if i was picking on him would i have said i thought his tunnels were a great idea? obviously, you missed that part of my post. people want him to stop talking about his tunnels. well, he stops if people stop mentioning his tunnels everytime he brings the subject up. just common sense my friend. correct? apology accepted.

Glad I missed tonight's excursions onto weird and wonderful topics. For the record, HurricaneChaser, I prefer you post on global warming and not the other stuff. And I'm impressed by your apology, as well as your weather knowledge.

For those who are tired of the global warming debates on here, it is THE issue of concern for climatologist and meteorologists so it is quite appropriate that we thrash it out here as well. Fact is, the earth is warming. Only question is how much we're contributing. No one knows for sure, but the models point to an increasing human-induced warming effect as the century wears on and greenhouse gas levels inexorably rise.

people, you want the tunnel talk to stop? then stop talking about them. everytime buster mentions something about his tunnels someone is always saying they won't work and he goes through the spiel once again. i think he's explained how they work about 50 times int he last five weeks or so. so, if you want the tunnel talk to end which i think is a good idea if they were to work, then quit responding to his posts. he gets no response eventually he'll stop posting about his tunnels. common sense.

Yes, you can say what you like here. Even though it's Dr. Masters' forum, and he has every right to control what appears here, he seems willing to tolerate almost anything. So, in fact, you don't have to go start your own blog in order to speak your piece.

in regards to all the comments from last night's "discussion", i have to agree with hurricane chaser. he was right in his comment about dr. master's making his political statements. some of you thought he should apoligise for what he said about dr. masters and he shouldn't. and i just read from an earlier comment from chaser in this discussion that he regrets what he said. why chaser? you were right. no regrets.

in my opinion dr.master's should apologise to us for making his politcal views public. yes, he should apologise to us. sure, it's his blog but, it's a WEATHER BLOG. not a political blog, nor religious blog. if i'm not mistaken the link on this site says "dr. jeff master's WEATHER blog". now, if he had another blog to discuss these issues (like he started in the wake of katrina) then that's fine.

now, i'm not personally attacking dr. masters whatsoever. i have the utmost respect for him and his scientific views. i've learned so much since june when i first began reading his blogs and i hope to learn more from his blog updates in the future but, i personally think he should keeps his personal political views out of his scientific discussions unless it's about cutting programs that will hurt future funding and research.

i know i'm going to get attacked on here but, like chaser said, when you stand up for your beliefs you get shot down quickly. plus, all of you want to look good for dr. masters and say i'm wrong and a disgrace but who are you to judge? just because i read this blog, learn alot from his topics that i never knew about, and send comments every onec in a blue moon does not mean i have to KISS THE BUTT of the blogger. i'm an american such as the rest of you so i don't have to agree with everything dr. masters says and i have the right to say i think he's wrong whether i'm wrong for saying that or not.

plus, the comments on here are very seldom about what the topic is anyway.

so, chaser stand your ground. you're right in what you said and i think dr. masters should apolgise to all his readers for the politcal propoganda he put out on his WEATHER BLOG. not a politcal blog but, a WEATHER BLOG.

unlike chaser, i will not respond to the attacks and names i will get called just to get the last word. i said what i have to say regarding this topic. all have a great night.

Hey Colby, I sent you a PM on your site about this already, but I have a GREAT and creepy scenario loosely based on 2 very historic hurricanes that I would like to execute on your fantasycast after we're done with yours. Would you mind if I did that?

I'm not certain that there is data to support that "we make more than volcanos" when it comes to NOx (Nitrogen Oxide) Colby.......but it sure does seem like we do. It's my opinion that that's one of our modern paradigms. The data (very limited) that I've had the fortune to see doesn't support that. I wish that it did.